This invention relates to thermally insulating composite materials, and more particularly, to improved cellular, cementitious materials and a process for making the same.
Inorganic materials such as fiberglass and so-called rock-wool find widespread application for residential housing. In U.S. Pat. No. 4,161,855 and U.S. Pat. No. 4,240,839, improved materials particularly suited for thermal insulation of building structures, such as residential housing, are disclosed. The thermal insulation materials in said patents comprise an inorganic, low-density foam with gypsum as the major constituent. In U.S. Pat. No. 4,161,855, the low-density cellular gypsum material has a dry density in the range of about 3 to about 6 lbs./ft..sup.3, and in U.S. Pat. No. 4,240,839, the low-density cellular gypsum material has a dry density of less than about 3 lbs./ft.sup.3.
While the prior art materials exhibit varying degrees of effectiveness as thermal insulators, none of the prior art materials appear to have sufficient rigidity to enable its use without independent structural support.